Increased collagenase activity in metastatic cells as a result of decreased TIMP expression

It has been postulated in a number of systems that increased metalloproteinase activity in different pathologies can be due to decreased levels of the specific inhibitor tissue inhibitor of metalloproteinases (TIMP). To date direct proof of such a mechanism has been lacking. We report that in metastatic variants which secrete increased levels of collagenase activity, this is due to decreased levels of TIMP activity and mRNA levels.